<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>??</title>
<style>
.ly1{width:100%; height:100px; background:blue;}
  .ly1-1{width:50%; height:100px; background:blue;float:left;}
  .ly1-2{width:50%; height:100px; background:green;float:left;}
  .ly1-3{clear:both;}
.ly2{width:100%; height:200px; background:orange;}
  .ly2-1{width:100%;height:100px;background:orange;}
    .ly2-1-1{width:33.33%;height:100px;background:orange;float:left;}
	.ly2-1-2{width:33.33%;height:100px;background:yellow;float:left;}
	.ly2-1-3{width:33.33%;height:100px;background:skyblue;float:left;}
	.ly2-1-4{clear:both;}
  .ly2-2{width:100%;height:100px;background:red;}
    .ly2-2-1{width:100%;height:50px;background:red;float:left;}
	.ly2-2-2{width:100%;height:50px;background:pink;float:left;}
	.ly2-2-3{clear:both;}
.ly3{width:100%; height:100px; background:green;}
</style>
</head>

<body>
<div class="ly1"><div class="ly1-1"></div><div class="ly1-2"><div class="ly1-3"></div></div></div>
<div class="ly2"><div class="ly2-1"><div class="ly2-1-1"></div><div class="ly2-1-2"></div><div class="ly2-1-3"></div><div class="ly2-1-4"></div></div><div class="ly2-2"><div class="ly2-2-1"></div><div class="ly2-2-2"></div><div class="ly2-2-3"></div></div></div>
<div class="ly3"></div>
</body>
</html>